The report highlights the fact that energy used in homes accounts for about 20% of the UK’s entire greenhouse gas emissions. It’s not enough to rely on newly built homes being more efficient, as 80% of the homes people will inhabit in 2050 have already been built.

Scaling Up Retrofit 2050 calls for a nationwide programme to boost the energy efficiency of existing homes through ‘deep retrofit’, stating that it’s the only way for the UK to achieve its carbon saving goals.

Deep retrofitting is a whole-house approach to upgrading energy efficiency in one step as opposed to a series of incremental improvements over a long period of time. It includes measures such as solar panels, insulation and ventilation, and sustainable heating systems.

As well as reducing the carbon emissions and energy requirements of the current housing stock, it makes cold homes warmer and healthier and reduces energy bills.

The IET said that current barriers to the development of a national programme include: a lack of customer demand; no effective policy driver for change; costs per home are too high as there is not yet a supply chain that can deliver deep retrofits cost-effectively, in volume and at speed; and a lack of initial financing.

“If we are to meet the 2050 targets of the Climate Change Act, then all housing in the UK must have zero carbon emissions from space and water heating, and space cooling,” said Rick Hartwig, IET Built Environment lead.

A national retrofit programme would not only help drive demand but allow greater scale to cut the costs per property, Hartwig pointed out.